This invention relates to wells for the production of oil or gas from underground formations. In one of its aspects this invention relates to the cement sheath around the well casing of such a well. In another of its aspects this invention relates to the repair of the cement sheath around such a well casing. In yet another aspect this invention relates to the use of gels in underground formations. In still another aspect this invention relates to squeeze cementing techniques in underground wells.
In the preparation of a well for tapping an underground formation to produce the gas and oil contained in the formation a casing is installed within a bore hole and the space between the wall of the bore hole and the outer face of the casing is filled with cementitious material which upon setting anchors the casing in place. Perforations are provided in the well casing in areas of the underground formation from which production is taken. It often happens that the cement sheath adjacent these perforated areas becomes broken away, cracked away from the well bore surface or cracked within the cement sheathing itself so that water can flow through or around the damaged sheathing. Sometimes the damaged areas allow an influx of water in sufficient amount to interfere with production of hydrocarbon products from the underground formation.
It is an object of this invention to provide a method for repairing a cement sheath around the casing in a well bore.
Other objects, aspects and the various advantages of this invention will be apparent upon reading the specification and the appended claims.